The high prevalence of myopia and its prominence as a public health problem emphasize the importance of gaining increased understanding of the genetic and environmental factors underlying refractive development in children, which the proposed analyses are designed to accomplish. The main goal is to create an integrated account of risk factors for the development of myopia by using new approaches for the analysis of longitudinal data that have been collected for up to 32 years and by performing these analyses to follow up on promising findings from the recent myopia literature. Our Access database has over 10,000 refractions, 110,000 accommodation measurements, and close to 2000 aberration measurements from 2090 subjects. To our knowledge this refraction database is the only one with longitudinal measurements starting in infancy. The analyses support a goal of the Strabismus, Amblyopia, and Visual Processing Program of the National Eye Institute for the next 5 years, which is to "determine the etiology of myopia in humans, identify the risk factors associated with myopia and other refractive errors, and identify the biochemical pathways associated with the control of eye growth." In addition to providing a risk profile for myopia development, results from the proposed analyses also may help to develop new methods to slow the progression of myopia and to identify good candidates for interventions for myopia control. The specific aims are as follows: Specific Aim 1: To study the development of refraction from infancy and to investigate the association of refractive errors in children, their siblings, and their parents. Specific Aim 2: To investigate environmental factors related to myopia development using new analytic approaches and data that have not been analyzed previously. Specific Aim 3: To integrate the factors identified in Aims 1 and 2 and those identified previously into a more complete account of risk factors for myopia development.